The subject matter of the invention is new alkenylacyloxysilanes, a method for producing them, and their use in pressure-sensitive adhesives.
It is known to use vinylalkoxysilanes as comonomers in the preparation of copolymers from ethylenically unsaturated monomers. Furthermore, pressure-sensitive adhesives are known which are prepared by the copolymerization of N-vinyl lactams and acrylic acid esters (German Publication DE-PS No. 19 64 743). The crosslinking of these pressure-sensitive adhesives is accomplished either by radiation or by means of organic peroxides.
U.S. Pat. No. 3,971,751 furthermore discloses adhesives made from polyethers having terminal silyl ether groups. In their crosslinking, the hydrolyzable groups (e.g., alkoxy groups) on the silyl terminal groups hydrolyze to form an Si-O-Si bond.
It has already been proposed to make use of the hydrolyzability of alkoxysilyl groups for crosslinking in pressure-sensitive adhesives on the basis of copolymers having ethylenically unsaturated groups (German Patent Application P No. 32 32 923.7), but only vinylalkoxysilanes are used as comonomers, whose alkoxy groups often hydrolyze but very slowly in the copolymers. Also, in the above-named adhesives having silyl ether terminal groups, the hydrolysis often takes so long, due to the alkoxy terminal groups, that pressure-sensitive systems which crosslink by hydrolysis of alkoxysilyl terminal groups involve disadvantages on account of the slowness of the hydrolysis.
The problem therefore existed of finding solvent-free pressure-sensitive adhesive systems which are based on copolymers of ethylenically unsaturated compounds, crosslink relatively rapidly, and form physiologically unobjectional and noncorrosive hydrolysis products.